Tissue tracking of segmental strain as a predictor of provoked dynamic left ventricular outflow tract obstruction

BackgroundLeft ventricular outflow tract obstruction (LVOTO) is commonly observed in patients with hypertrophic cardiomyopathy (HCM) or left ventricular hypertrophy (LVH). Some patients develop LVOTO provoked by physical exertion, and hence termed dynamic LVOTO (DLVOTO). However, its precise prevalence and mechanism are still unclear.AimTwo-dimensional speckle tracking echocardiography (2D STE) seems to be helpful for the detection of early LV structural abnormalities. This study aimed to examine the possible role of segmental as well as global longitudinal strain in identifying DLVOTO non-HCM patients as detected by dobutamine stress echocardiography (DSE).Methods and resultsTwo hundred and fifty patients without structural heart disease had undergone conventional transthoracic echocardiography, 2D STE, and DSE. All patients with non-ischemic evidence were divided into two groups according to the DSE results; DLVOTO (+) and DLVOTO (?).Among 250 patients, 50 patients (36%) had shown DLVOTO after DSE (15 males, 35 females; mean age 55±7years). They were compared with 90 non -LVOTO obstruction patients (43 males, 47 females; mean age 57±6years). Based on multivariate logistic regression analysis, the independent predictors of provoked DLVOTO during DSE were resting basal septal longitudinal strain BS-LS _average (p < 0.001), resting LA reservoir strain (p < 0.001), and systolic LVOT diameter (p = 0.03). Resting BS-LS _average with cut-off - 17.5% was recognized as a critical indicator of DLVOTO, with sensitivity 78%, and specificity 95% (better than systolic LVOT diameter of sensitivity 76%, and specificity 15% and resting LA reservoir strain which showed poor AUC at ROC curve 0.007).ConclusionWe demonstrate that provoked LVOTO during DSE in non HCM symptomatic patients is directly correlated to resting regional LS, where the increased BS-LS of ≥ ?17.5% was a key determinant of LVOT gradient provocation. Assessment of baseline BS-LS _average might be a bedside simple tool for detection of patients with DLVOTO not able to do DSE.     

多巴酚丁胺负荷试验结合脉冲组织多普勒二尖瓣环运动定量评估心肌梗死患者心肌存活

目的研究脉冲多普勒组织成像技术(DTI-PW)中二尖瓣环速度检测存活心肌的可行性及价值.方法 40例陈旧性心肌梗死患者室壁按照硝酸甘油(NTG)介入99Tcm-MIBI SPECT 结果分为有存活心肌组、无存活心肌组,采用小剂量多巴酚丁胺负荷超声心动图试验,测量相应梗死壁二尖瓣环多巴酚丁胺(Dobutamine,Dob)负荷前及每级Dob负荷试验时的收缩期峰值速度Vs、射血前期PEP、射血期ET;另选20例年龄匹配的正常人为对照组,测量6个室壁二尖瓣环Vs、PEP、ET.结果 Dob 5μg/(kg·min)时,以Vs增加量≥2 cm/s为临界值,则检测存活心肌的敏感度为75%,特异度为76%,准确度为75%,以PEP/ET变化率2(Dob 5μg/(kg·min)时PEP/ET与Dob负荷前PEP/ET的比值)≥100%作为诊断无存活心肌的临界值,则敏感度为73%,特异度为85%,准确度为79%;以Dob 10 μg/(kg·min)时Vs增加量≥3 cm/s为临界值,则检测存活心肌的敏感度增加到83%,特异度为79%,准确度增加到81%,以PEP/ET变化率3(Dob 10μg/(kg·min)时PEP/ET与Dob负荷前PEP/ET的比值)≥100%作为诊断非存活心肌的临界值,则敏感度为82%,特异度为85%,准确度为84%.结论 Dob负荷时二尖瓣环Vs、PEP/ET可用于检测存活心肌,方法简单、可靠.     

实时三维超声心动图定量评价心肌梗死犬多巴酚丁胺负荷实验中左室容积的变化

目的　应用实时三维超声心动图 (RT- 3DE)定量评价心肌梗死犬多巴酚丁胺负荷实验 (DSE)过程中左室容积的变化。方法　建立犬急性心肌梗死模型。分别对 12条犬在冠脉结扎前及冠脉结扎 180 min-再灌注 30 min后行 DSE。应用 RT- 3DE获取犬静息 (rest)及输注多巴酚丁胺 (Dob) 5、 10、 2 0、 30、 4 0 μg/ (kg·min)及终止后 5 min时 (recovry)的 RT- 3DE容积数据库 ,根据心尖长轴 8平面法勾画左室舒张末期容积 (L VEDV)及收缩末期容积 (L VESV) ;计算其从静息至峰值负荷时的容积变化分数 ΔVLVEDV%及 ΔVL VESV%。结果　 (1)冠脉结扎前 :随 Dob剂量的逐级增加 ,平均 L VEDV和 L VESV明显减小 ;冠脉结扎 180 min-再灌注 30 min后 :平均 L VEDV和 L VESV在 Dob<2 0 μg/ (kg· min)时也呈减小趋势 ,但在 Dob≥ 2 0 μg/ (kg·min)时则明显增大。两者呈不同的变化趋势 ;(2 )冠脉结扎前及冠脉结扎 180 min-再灌注 30 min后平均ΔVL VEDV%分别为 14 .75 %及 7.95 % (n=12 ,P=0 .0 0 1) ;平均 ΔVLVESV%分别为 39.86 %及 2 0 .75 % (n=12 ,P<0 .0 0 1)。后者明显小于前者。结论　通过应用 RT- 3DE分析 DSE过程中左室容积的变化 ,可以区分正常犬与心肌梗死犬。     

小剂量多巴酚丁胺负荷超声心动图结合多普勒组织成像评价存活心肌的研究

目的：研究多普勒组织成像（DTI）结合小剂量多巴酚丁胺负荷超声心动图评价心肌活性的可行性，并研究其与^99mTc-MIBI硝酸甘油介入心肌显像在评价存活心肌方面的一致性。方法：对30例经冠状动脉造影确冠心病的患者行超声心动图及心脏核素检查，超声心动图检查使用DTI速度模式，采用两级多巴酚丁胺超声心动图试验，所有患者均行静息显像及硝酸甘油介入后显像，结果：（1）30例冠心病患者用超声心动图静息DTI检测480个室壁节段，检出166个运动常节段，运动减弱节段108个，运动消失节段58个。（2）对患者行超声心动图小剂量多巴酚丁胺负荷试验DTI检测480个室壁节段，检出166个运动异常节段中89个节段运动改善，提示为存活心肌节段（A组）；余77个节段无变化，为坏死心肌（B组）。A组静息及负荷超声心动图DTI差异有显著性意义（P＜0．05），B组静息及负荷超声心动图DTI差异无显著性意义（P＞0．05）。A组与B组静息超心动图DTI差异无显著性意义（P＞0．05）。（3）30例冠心病患者用^99mTc-MIBI硝酸甘油介入心肌显像检测480个室壁节段，检出185个病变节段，其中97个为存活心肌节段，小剂量多巴酚丁胺结合超声心动图DTI诊断存活心肌的敏感性达83％，特异性达86％，结论：DTI结合小剂量多巴酚丁胺是评心肌活性的一项超声新技术，其结果与^99mTc-MIBI硝酸甘油介入心肌显像进行对照分析显示良好的一致性，应用前景较为乐观。     

微量注射泵泵入硝酸甘油、多巴胺、多巴酚丁胺治疗难治性心力衰竭的临床效果观察

目的：观察应用微量注射泵泵入硝酸甘油、多巴胺、多巴酚丁胺治疗难治性心力衰竭的临床疗效。方法选择2011年1月~2014年1月本院102例心功能Ⅲ~Ⅳ级(NYHA分级法)的住院患者,在卧床休息、控制饮食、吸氧、强心剂及利尿剂治疗的基础上,应用微量注射泵泵入硝酸甘油、多巴胺、多巴酚丁胺,疗程3~5d,观察患者临床症状、体征、心功能改善情况。结果102例患者用药后临床症状和心功能各项参数均明显改善,与治疗前比较,差异有统计学意义(P<0.05)。结论应用微量泵泵入硝酸甘油、多巴胺、多巴酚丁胺治疗难治性心力衰竭患者疗效明显,安全可靠。     

The effect of dobutamine infusion on splanchnic blood flow and oxygen transport in patients with acute pancreatitis

Objectives: To measure the blood flow distribution and oxygen transport in pancreatitis and to evaluate the regional effects of increased systemic blood flow. Design: Nonrandomized controlled trial. Setting: A general intensive care unit in a tertiary care center. Patients: 10 patients with pancreatitis requiring mechanical ventilation were studied after fluid resuscitation, and for the response to dobutamine, the patients served as their own controls. For the baseline, 11 patients scheduled for elective abdominal surgery served as a control group. Interventions: Systemic and regional hemodynamics were measured after fluid resuscitation to predefined hemodynamic endpoints. In patients with pancreatitis, the measurement was repeated after cardiac output had been increased by at least 25 % by dobutamine. Measurements and results: Hepatosplanchnic blood flow was estimated using regional catheterization and the dye dilution method. In patients with pancreatitis, the cardiac index did not differ from that of the control group (3.9 ± 0.8 vs 4.1 ± 0.7 l · min^–1· m^–2;NS). Accordingly, there was no difference in the splanchnic blood flow (1.1 ± 0.4 vs 1.2 ± 0.5 l · min^–1· m^–2;NS). Systemic and splanchnic oxygen consumption was increased in patients with pancreatitis (179 ± 25 vs 147 ± 27 ml · min^–1· m^–2, p < 0.05 and 68 ± 15 vs 49 ± 19 ml · min^–1· m^–2, p < 0.05), and systemic and splanchnic oxygen extraction was higher (0.34 ± 0.08 vs23 ± 0.05, p < 0.01 and 0.46 ± 0.18 vs 0.28 ± 0.08, p < 0.05, respectively). Dobutamine had inconsistent effects on splanchnic blood flow: in individual patients, splanchnic blood flow even decreased substantially. Conclusions: In severe pancreatitis, oxygen consumption is increased in the splanchnic region; increased splanchnic oxygen demand is not always met by adequately increased blood flow. Increasing the systemic blood flow with dobutamine does not improve perfusion in the splanchnic bed. Received: 24 September 1996 Accepted: 5 May 1997     

应用定量组织速度成像技术结合小剂量多巴酚丁胺负荷试验评价心肌存活性

目的　探讨应用定量组织速度成像 (QTVI)技术结合小剂量多巴酚丁胺负荷超声心动图试验 (LDDSE)评价心肌存活性的价值。方法　 2 0例心肌梗死患者均行经皮腔内冠状动脉成形术 (PTCA)或PTCA 支架术。术前 1周内进行LDDSE ,术后 ( >6周 )复查超声心动图。应用QTVI技术获取LDDSE各阶段及术后梗死心肌范围内相邻两取样点的组织速度和位移曲线 ,测量其收缩期最大速度和位移 ,算出其心肌应变 (S)和应变率 (SR)。结果　在术后室壁运动有改善组中 ,LDDSE各阶段以及术后各取样点的收缩期最大速度和最大位移均较术前静息状态时有不同程度提高。LDDSE在 5 μg·kg-1·min-1剂量结束时 ,SR、S均较静息状态时提高 [SR :( 0 .4± 0 .3 )s-1对 ( 0 .2± 0 .2 )s-1,P <0 .0 5 ;S :0 .0 5± 0 .0 4对 0 .0 3±0 .0 1,P <0 .0 5 ] ,而较术后稍低 [SR :( 0 .4± 0 .3 )s-1对 ( 0 .8± 0 .2 )s-1,P <0 .0 5 ;S :0 .0 5± 0 .0 4对 0 .10±0 .0 4,P <0 .0 5 ]。LDDSE在 10 μg·kg-1·min-1剂量结束时 ,SR、R均较静息状态时明显提高 [SR :( 1.0±0 .4)s-1对 ( 0 .2± 0 .2 )s-1,P <0 .0 1;S :0 .10± 0 .0 5对 0 .0 3± 0 .0 1,P <0 .0 1] ,与术后差异无显著性意义[SR :( 1.0± 0 .4)s-1对 ( 0 .8± 0 .2 )s-1,P >0 .0 5 ;S :